This invention relates to devices for enclosing objects, especially, although not necessarily, for enclosing elongate objects, for example, pipes and cables.
It is often desirable to enclose objects, and especially elongate objects such as pipes and cables, in a cover, for example in order to protect the object from the environment or from mechanical abuse. Of particular interest are those devices that are dimensionally recoverable and can be installed at any point on the object without requiring access to its end. Such devices are commonly known as wrap-around devices. One form of wrap-around device that has been used extensively for a number of years is described in U.S. Patent Specification No. 3,455,336, the disclosure of which is incorporated herein by reference. This wrap-around device has a mechanical closure arrangement in which the closure portions of the cover are provided with axially extending ridges which together form a rail over which a metal channel can be positioned to retain the edge portions together. Wrap-around devices having adhesive closure arrangements have also been proposed in which the closure portions of the cover are provided with a layer of contact or pressure sensitive adhesive so that one closure portion can be placed over the other closure portion to form a lap joint along the length of the device. A major problem that has been encountered with wrap-around devices having adhesive closure arrangements is that it is very difficult to ensure that the closure portions are correctly aligned, especially where the wrap-around device can exceed one meter in length, since the installer must retain one closure portion on the object so that it does not move while, at the same time, positioning the other closure portion over it and then pressing the two together. A large degree of misalignment will cause the closure portions to buckle or be forced apart on recovery of the wrap-around device, while a small degree of misalignment may cause buckling which is undetectable but which will allow passage of fluid through the bond and so render the device ineffective. It will be appreciated that any misalignment cannot be corrected once any part of the closure portions have contacted each other.